1. Technical Field
The present disclosure relates to a surgical instrument and method for performing anastomosis of tubular body structures, and more particularly to an instrument for performing vascular anastomoses.
2. Background of Related Art
Anastomoses of tubular body structures may be performed for a number of different procedures. One general example of an anastomosis is a vascular anastomosis wherein two blood vessels are joined together to permit blood flow therebetween. A specific example of vascular anastomosis is an arteriovenous fistula (xe2x80x9cA-V fistulaxe2x80x9d) which is performed to facilitate hemodialysis for end stage kidney disease. The procedure usually consists of an end to side anastomosis joining an artery and a vein in the forearm, e.g., joining the radial artery end to side with the cephalic (radial) vein or the ulnar artery with the basilic (ulnar) vein. It can also be performed in the leg, but usually after all the arm sites have been exhausted. The A-V fistula allows a single puncture at the dialysis unit for blood cleansing. The fistula allows a greater flow and outflow rate through the dialyzer.
Another specific example of a vascular anastomosis is a coronary artery bypass graft (xe2x80x9cCABGxe2x80x9d). Coronary artery disease is often characterized by lesions or occlusions in the coronary arteries which may result in inadequate blood flow to the myocardium, or myocardial ischemia, which is typically responsible for such complications as angina pectoris, necrosis of cardiac tissue (myocardial infarction), and sudden death. In some cases, coronary artery disease may be treated by the use of drugs and by modifications in behavior and diet. In other cases, dilatation of coronary arteries may be achieved by such procedures as angioplasty, laser ablation, atherectomy, catheterization, and intravascular stents.
For certain patients, a CABG procedure is the preferred form of treatment to relieve symptoms and often increase life expectancy. A CABG procedure consists of direct anastomosis of a vessel segment to one or more of the coronary arteries. For example, a reversed segment of the saphenous vein may be grafted at one end to the ascending aorta as an arterial blood source and at the other end to a coronary artery at a point beyond the arterial occlusion. Alternatively, the internal mammary artery (IMA) is located in the thoracic cavity adjacent the sternum and is likewise suitable for grafting to a coronary artery, such as the left anterior descending artery (LAD).
The performance of a CABG procedure typically requires access to the heart, blood vessels and associated tissue. Access to the patient""s thoracic cavity may be achieved in an open procedure by making a large longitudinal incision in the chest. This procedure, referred to as a median sternotomy, requires a saw or other cutting instrument to cut the sternum and allow two opposing halves of the rib cages to be spread apart. U.S. Pat. No. 5,025,779 to Bugge discloses a retractor which is designed to grip opposite sternum halves and spread the thoracic cavity apart. The large opening which is created by this technique enables the surgeon to directly visualize the surgical site and perform procedures on the affected organs. However, such procedures that involve large incisions and substantial displacement of the rib cage are often traumatic to the patient with significant attendant risks. The recovery period may be extensive and is often painful. Furthermore, patients for whom coronary surgery is indicated may need to forego such surgery due to the risks involved with gaining access to the heart.
U.S. Pat. No. 5,503,617 to Jako discloses a retractor configured to be held by the surgeon for use in vascular or cardiac surgery to retract and hold ribs apart to allow access to the heart or a lung through an operating xe2x80x9cwindowxe2x80x9d. The retractor includes a rigid frame and a translation frame slidably connected to the rigid frame. Lower and upper blades are rotatably mounted to the rigid frame and the translation frame respectively. The xe2x80x9cwindowxe2x80x9d approach enables the surgeon to gain access through a smaller incision and with less displacement of the ribs, and consequently, less trauma to the patient.
Once access to the thoracic cavity has been achieved, surgery on the heart may be performed. Such procedures typically require that the heart beat be arrested while maintaining circulation throughout the rest of the body. Cardioplegic fluid, such as potassium chloride (KCl) is delivered to the blood vessels of the heart to paralyze the myocardium. As disclosed in WO 95/15715 to Sterman et al. for example, cardioplegic fluid is infused into the myocardium through the coronary arteries by a catheter inserted into the ascending aorta. Alternatively, cardioplegic fluid is infused through the coronary veins in a retrograde manner by a catheter positioned in the interior jugular vein accessed at the patient""s neck. Such procedures require the introduction of multiple catheters into the blood vessels adjacent the heart, which is complicated procedure requiring that the desired vessels be properly located and accessed. The progression of the guide wires and catheters must be closely monitored to determine proper placement. Furthermore, the introduction of catheters forms punctures in the blood vessels that must be subsequently closed, and there is an increased risk of trauma to the interior walls of the vessels in which the catheters must pass.
Alternatively, the CABG procedure may be performed while the heart is permitted to beat. Such a procedure is now commonly referred to as minimally invasive direct coronary artery bypass (MIDCAB). A surgical instrument is used to stabilize the heart and restrict blood flow through the coronary artery during the graft procedure. Special care must be given to procedures performed on a beating heart, e.g. synchronizing procedures to occur at certain stages in the cardiac cycle, such as between heartbeats.
To perform a CABG procedure, the harvested vessel segment, such as the IMA, is grafted to the coronary artery by end-to-side anastomosis. Typically, sutures are used to graft the vessel segments. However, conventional suturing is complicated by the use of minimally invasive procedures, such as the window approach. Limited access and reduced visibility may impede the surgeon""s ability to manually apply sutures to a graft. Additionally, it is difficult and time consuming to manually suture if the CABG procedure is being performed while the heart is beating as the suturing must be synchronized with the heart beat.
The process of manually suturing the harvested vessel segment to a coronary artery is time consuming and requires a great deal of skill on the part of the surgeon. The resulting sutured anastomosis will also be dependent on the skills of the surgeon. In minimally invasive procedures such as in MIDCAB, the ability to suture is even more complicated due to limited maneuverability and reduced visibility. U.S. Pat. No. 5,707,380 to which issued on Jan. 3, 1998 to Hinchliffe et al., the entire contents of which are hereby incorporated by reference, discloses an apparatus and a procedure that enables the remote anastomosis without piercing of vessels during both conventional and minimally invasive procedures. A continuing need exists, however, for improved surgical instruments and methods for performing remote anastomoses during both conventional and minimally invasive procedures.
The present disclosure provides a surgical instrument for performing an anastomosis, which includes a housing having a proximal end and a distal end; a shaft extending from the housing distal end; and a disposable loading unit configured and dimensioned to retain a plurality of surgical fasteners, the disposable loading unit extending from the shaft and forming a juncture with the shaft, the disposable loading unit including: i) opposed split-sections pivotably connected to facilitate movement of the opposed split-sections between open and closed configurations, the opposed split sections being movable through a firing stroke from a first position to a second position and back to the first position to form a plurality of surgical fasteners; and ii) a pivot lockout member including a latch portion which extends between the opposed split-sections, the latch portion including a contact surface which interacts with a corresponding surface formed on at least one of the opposed split-sections to retain the opposed split-sections in the closed configuration, wherein upon return of the fastener pusher member to the first position from the second position, the pivot lockout member is displaced relative to the opposed split sections to an unlocked configuration.
A lock member is disposed relative to the juncture of the disposable loading unit and the shaft, the lock member operable from the housing and movable between an unlocked position wherein the disposable loading unit is unsecured relative to the shaft and a locked position wherein the disposable loading unit is secured relative to the shaft. The lock member may further be biased towards the locked position.
An actuator lever is disposed on the housing and operatively associated with the opposed split sections such that movement of the actuator lever from an initial position to a secondary position effects movement of the opposed split sections being from the first position to the second position to effect deformation of the plurality of surgical fasteners.
A firing safety assembly is provided which operatively interacts with the actuator lever to prevent unintended movement of the actuator lever from the initial position to the secondary position. The firing safety assembly is normally biased towards a locked out configuration.
In a particular aspect of the present disclosure, the shaft and the disposable loading unit each define respective central longitudinal axes which are substantially axially aligned with each other.
In a further embodiment of the present disclosure, a surgical instrument for performing an anastomosis is provided which includes a housing having a proximal end and a distal end, a shaft extending from the housing distal end; a disposable loading unit rotatably and detachably extending from the shaft and forming a juncture with the shaft, the disposable loading unit including: i) a fastener support member configured and dimensioned to support a plurality of surgical fasteners in a predetermined array of a generally close-ended geometric configuration; and ii) a fastener pusher member disposed adjacent the fastener support member, the fastener pusher member being movable from a first position relative to the plurality of surgical fasteners to a second position relative to the plurality of surgical fasteners so as to deform the plurality of surgical fasteners to a tissue gripping orientation; and a lock member disposed relative to the juncture of the disposable loading unit and the shaft, the lock member operable from the housing and movable between an unlocked position wherein the disposable loading unit is unsecured relative to the shaft and a locked position wherein the disposable loading unit is secured relative to the shaft.
An actuator lever is disposed on the housing and operatively associated with the fastener pusher member such that movement of the actuator lever from an initial position to a secondary position effects movement of the fastener pusher member from the first position to the second position to effect deformation of the plurality of surgical fasteners.
An actuator rod is also provided which is connected to the actuator lever and wherein the disposable loading unit further includes an actuator member which interacts with the actuator lever to effect movement of the fastener pusher member from the first position to the second position to effect deformation of the surgical fasteners.
A firing safety assembly is also provided which operatively interacts with the actuator lever to prevent unintended movement of the actuator lever from the initial position to the secondary position. The firing safety assembly may normally be biased towards a locked out configuration.
In a particular aspect of the present disclosure, the shaft and the fastener pusher member each define respective central longitudinal axes which are substantially axially aligned with each other.
In another aspect of the present disclosure, the fastener support member and the fastener pusher member are each formed of respective opposing split-sections, at least two of the split-sections being pivotably connected to facilitate movement of the opposed split-sections between open and closed configurations. A pivot lockout member is also provided which extends between the opposed split-sections and includes a contact surface which interacts with a corresponding surface formed on at least one of the opposed split-sections to retain the opposed split-sections in the closed configuration. Optionally, the fastener pusher member is biased to return to the first position after movement to the second position. A particular feature of the present disclosure is that upon return of the fastener pusher member to the first position from the second position, the pivot lockout member is displaced to an unlocked configuration.
In a further alternative embodiment, the present disclosure also provides a disposable loading unit for a surgical anastomosis instrument, which includes an elongated fastener support member defining a pathway extending at least partially therethrough and including a first opening at a distal end thereof and a second opening spaced from the distal end and in communication with the pathway, the second opening configured and dimensioned to receive a tubular vessel therethrough such that the tubular vessel can pass through the pathway and extend outward from the first opening at the distal end, the fastener support member further including a plurality of spaced apart retention slots defined therein, each retention slot being adapted to support a respective surgical fastener of a plurality of surgical fasteners; a fastener pusher member disposed adjacent the fastener support member, the fastener pusher member movable from a first position relative to the plurality of surgical fasteners to a second position relative to the plurality of surgical fasteners so as to deform the plurality of surgical fasteners; an actuator operatively associated with the fastener pusher member to effect movement of the fastener pusher member from the first position to the second position; and a mounting hub disposed adjacent the actuator and defining an access opening, such that a portion of the actuator is accessible through the access opening, the mounting hub being configured and dimensioned to be removably and rotatably attached to a distal portion of the surgical instrument thereby facilitating removable attachment of the disposable loading unit to the surgical instrument.
In one aspect of the embodiment, the fastener support member and the fastener pusher member are each formed of respective opposing split-sections, at least two of the split-sections being pivotably connected to facilitate movement of the opposed split-sections between open and closed configurations. A further feature of the embodiment is a pivot lockout member which extends between the opposed split-sections and includes a contact surface which interacts with a corresponding surface formed on at least one of the opposed split-sections to retain the opposed split-sections in the closed configuration. In a further aspect of the embodiment, the fastener pusher member is biased to return to the first position after movement to the second position.
In a further unique feature of the present disclosure, upon return of the fastener pusher member to the first position from the second position, the pivot lockout member is displaced to an unlocked configuration.
The present disclosure also provides a method of performing a vascular anastomosis which includes the steps of providing a disposable loading unit having a fastener support member defining a passage therethrough for reception of a first vessel, a plurality of surgical fasteners supported by the fastener support at a distal end thereof; positioning an end of the first vessel through the passage and everting the end of the vessel over the distal end of the fastener support adjacent the plurality of surgical fasteners; engaging the first vessel with the surgical fasteners; inserting the distal edge of the fastener support into an opening in a side wall of a second vessel; engaging the side wall of the second vessel with the surgical fasteners adjacent the opening; connecting the disposable loading unit to an actuator handle assembly after step e) such that the disposable loading unit is rotatable with respect to the actuator handle assembly; and deforming the legs of each surgical fastener by actuation of the actuator handle assembly to secure the first and second vessels together in fluid communication with each other.
In a further aspect of the presently disclosed method, an additional step is provided of removing the first vessel from the disposable loading unit by opening a split-section of the disposable loading unit.